Accessing the FTDI UART from Linux?


earlz

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I can easily program my Papilio with papilio-loader, but I can't access the built in uart.

I uploaded the Quickstart bitstream, but I don't see any tty for reading the ASCII table from Linux and there doesn't seem to be any documentation about this.

What exactly could the tty be called or how to access it?

I'm using Arch Linux 64bit, completely up to date.

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You should see ttyUSB0 and ttyUSB1. ttyUSB0 will disappear after you enter program mode with papilio loader, but ttyUSB1 will still be available.

After you connect you board to USB port, type "dmesg". You should see some USB stuff there.

Or eventually your distro does not have FTDI USB driver installed (it comes with standard kernel), but I think it does according to what I saw in forums.

Alvie

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I installed libftdi, but ttyUSB1 still didn't show up. (no idea, how the programmer works, because initially I didn't even have libftdi installed).. but then I restarted my computer (also after updating the kernel to latest) and now all works fine. Not sure why it didn't show up because other FTDI devices had no problems, such as my mbed and Arduino

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The libftdi library only provide access to low-level functions of the FTDI chips (it is the free equivalent to libftd2xx).

The devices enumeration as /dev/ttyUSBx is handled by the kernel modules to emulate standard UART over USB.

That's the reason why you were able to program the Papilio even before installing the library.

For your enumeration problem, I can only guess that updating your kernel allowed newer drivers to enumerate the FTDI as two UART.

Have a nice day.

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